Synthesis for producing ordered polyblock copolymers having a controllable molecular weight distribution

Abstract

The present invention relates to a process for the sequential and convergent preparation of ordered block copolymers comprising at least one non-polar and one polar polymer block, wherein the non-polar block is built up from specific monomers via a living sequential anionic polymerization by means of a Li-organyl initiator having a pKa greater than or equal to 45 and the polar block is a polymer block having a molecular weight greater than or equal to 350 g/mol and less than or equal to 5000 g/mol and being built up from monomers selected from the group consisting of C2-C10 oxacyclo compounds, their derivatives or mixtures of at least two different monomers thereof, wherein the polar polymer block is covalently linked to the non-polar block anion in a single step via an epoxy functionalization of one of the monomers of the polar block, obtained via a reaction of this monomer with epichlorohydrin, in a non-polar solvent in the presence of free Li ions. Furthermore, the present invention relates to specific block copolymers having short polar chains of very uniform chain length, polymer electrolytes, and the use of the block copolymers as polymer electrolytes in secondary alkaline batteries.

The invention claimed is: 
     
         1 . A process for the sequential and convergent preparation of ordered block copolymers comprising at least one non-polar and one polar polymer block, characterized in that the non-polar block is built up via a living sequential anionic polymerization by means of a Li-organyl initiator having a pKa greater than or equal to 45 from monomers selected from the group consisting of conjugated dienes, styrene, vinylsilane, vinylnaphthalene, vinylmetallocene, their derivatives or mixtures thereof and the polar block is a polymer block having a molecular weight greater than or equal to 350 g/mol and less than or equal to 5000 g/mol and being composed of monomers selected from the group consisting of C2-C10 oxacyclo compounds, their derivatives or mixtures of at least two different monomers thereof, the polar polymer block being covalently linked in a convergent manner to the non-polar block anion via an epoxy functionalization of one of the monomers of the polar block, obtained via a reaction of this monomer with epichlorohydrin, in a non-polar solvent in the presence of free Li ions. 
     
     
         2 . Process according to  claim 1 , wherein the polar block is a polyethylene oxide block. 
     
     
         3 . Process according to  claim 1 , wherein the nonpolar solvent is selected from the group of aromatic hydrocarbons or mixtures thereof. 
     
     
         4 . Process according to  claim 1 , wherein the Li-organyl initiator is an alkylithium initiator having a pKa greater than or equal to 50. 
     
     
         5 . Block copolymer obtained by a process according to  claim 1 . 
     
     
         6 . Block copolymer according to  claim 5 , wherein the polar block and the whole block copolymer have a polydispersity of greater than or equal to 1.0 and less than or equal to 1.05. 
     
     
         7 . Block copolymer according to  claim 5 , wherein the block copolymer has a molecular weight greater than or equal to 20 kg/mol and less than or equal to 250 kg/mol. 
     
     
         8 . Block copolymer according to  claim 5 , wherein the polar polymer block is a polyethylene oxide block, wherein the polyethylene oxide block has a molecular weight greater than or equal to 450 g/mol and less than or equal to 3000 g/mol. 
     
     
         9 . Block copolymer according to  claim 5 , wherein the nonpolar polymer block is a polyisoprene-polystyrene diblock polymer and polar polymer block is a polyethylene oxide block, wherein the weight ratio of polar to non-polar block polymer fractions, expressed as weight polar block divided by weight total block polymer, is greater than or equal to 0.5% and less than or equal to 10%. 
     
     
         10 . An alkali ion battery having a polymer electrolyte comprising the copolymer according to  claim 5 . 
     
     
         11 . The alkali ion battery according to  claim 10 , wherein the EO/alkali ion ratio in the polymer electrolyte of the alkaline ion battery is greater than or equal to 1:1 and less than or equal to 1:20. 
     
     
         12 . Polymer electrolyte for an alkali ion battery, characterized in that the polymer components of the polymer electrolyte comprise the block copolymers according to  claim 5 . 
     
     
         13 . Polymer electrolyte according to  claim 12 , wherein the polymer components of the polymer electrolyte consist of the block copolymers. 
     
     
         14 . Polymer electrolyte according to  claim 12 , wherein the polymer electrolyte has an ionic conductivity at −20° C. greater than or equal to 1 mS/cm. 
     
     
         15 . Polymer electrolyte according to  claim 12 , wherein the polymer electrolyte has an ionic conductivity of greater than or equal to 1 mS/cm in a temperature range of greater than or equal to −20° C. and less than or equal to 90° C. 
     
     
         16 . Polymer electrolyte according to  claim 12 , wherein the polymer electrolyte has a residual solvent content of greater than or equal to 0.1 wt % and less than or equal to 30 wt %.